public sealed override async Task RegisterCodeFixesAsync(CodeFixContext context)
        {
            SyntaxNode root = await context.Document.GetSyntaxRootAsync(context.CancellationToken).ConfigureAwait(false);

            MemberDeclarationSyntax memberDeclaration = root
                                                        .FindNode(context.Span, getInnermostNodeForTie: true)?
                                                        .FirstAncestorOrSelf <MemberDeclarationSyntax>();

            string name = ExtractTypeDeclarationToNewDocumentRefactoring.GetIdentifier(memberDeclaration).ValueText;

            CodeAction codeAction = CodeAction.Create(
                ExtractTypeDeclarationToNewDocumentRefactoring.GetTitle(name),
                cancellationToken => ExtractTypeDeclarationToNewDocumentRefactoring.RefactorAsync(context.Document, memberDeclaration, cancellationToken),
                DiagnosticIdentifiers.DeclareEachTypeInSeparateFile + BaseCodeFixProvider.EquivalenceKeySuffix);

            context.RegisterCodeFix(codeAction, context.Diagnostics);
        }
        public sealed override async Task RegisterCodeFixesAsync(CodeFixContext context)
        {
            SyntaxNode root = await context.GetSyntaxRootAsync().ConfigureAwait(false);

            if (!TryFindFirstAncestorOrSelf(root, context.Span, out MemberDeclarationSyntax memberDeclaration))
            {
                return;
            }

            string name  = ExtractTypeDeclarationToNewDocumentRefactoring.GetIdentifier(memberDeclaration).ValueText;
            string title = ExtractTypeDeclarationToNewDocumentRefactoring.GetTitle(name);

            CodeAction codeAction = CodeAction.Create(
                title,
                cancellationToken => ExtractTypeDeclarationToNewDocumentRefactoring.RefactorAsync(context.Document, memberDeclaration, cancellationToken),
                GetEquivalenceKey(DiagnosticIdentifiers.DeclareEachTypeInSeparateFile));

            context.RegisterCodeFix(codeAction, context.Diagnostics);
        }